U.S. patent application number 10/235748 was filed with the patent office on 2003-01-16 for slide inclination correcting method and slide inclination correcting apparatus in press machinery.
This patent application is currently assigned to Komatsu Ltd.. Invention is credited to Honma, Hiroaki, Mukai, Yoshiro, Takano, Katsuhiro.
Application Number | 20030010077 10/235748 |
Document ID | / |
Family ID | 27333840 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030010077 |
Kind Code |
A1 |
Mukai, Yoshiro ; et
al. |
January 16, 2003 |
Slide inclination correcting method and slide inclination
correcting apparatus in press machinery
Abstract
Disclosed are a slide inclination correcting method and a slide
inclination correcting apparatus in press machinery having a slide
drive mechanism disposed in a top area of a press machine for
driving a slide via a plurality of points to vertically move it up
and down, thereby forming a work piece. According to the invention,
the method and apparatus include the steps of, and means for,
finding by measurement or computation for each of dies or die sets
an eccentric load that is to develop in the slide in the process of
forming a work piece to prepare a die based slide inclination
correcting data for each of the dies or die sets; and on the basis
of the die based slide inclination correcting data prepared,
pre-imparting to the slide a compensatory amount of inclination
which corresponds to a predicted amount of inclination caused the
slide due to the eccentric load found.
Inventors: |
Mukai, Yoshiro;
(Komatsu-shi, JP) ; Honma, Hiroaki; (Nomi-gun,
JP) ; Takano, Katsuhiro; (Komatsu-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN & HATTORI, LLP
1725 K STREET, NW.
SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
Komatsu Ltd.
Tokyo
JP
|
Family ID: |
27333840 |
Appl. No.: |
10/235748 |
Filed: |
September 6, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10235748 |
Sep 6, 2002 |
|
|
|
09653192 |
Aug 31, 2000 |
|
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Current U.S.
Class: |
72/17.2 |
Current CPC
Class: |
B30B 15/0041 20130101;
F15B 11/22 20130101; B30B 15/007 20130101 |
Class at
Publication: |
72/17.2 |
International
Class: |
B21D 055/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 1999 |
JP |
P11-249509 |
Oct 22, 1999 |
JP |
P11-300466 |
Oct 25, 1999 |
JP |
P11-302080 |
Claims
What is claimed is:
1. A slide inclination correcting method in press machinery having
a slide drive mechanism disposed in a top area of a press machine
for driving a slide via a plurality of points to vertically move it
up and down, thereby forming a work piece, the method comprising
the steps of: finding by measurement or computation for each of
dies or die sets an eccentric load that is to develop in the slide
in the process of forming a work piece to prepare, a die based
slide inclination correction data for each of the dies or die sets;
and on the basis of the die based slide inclination correction data
prepared, pre-imparting to the slide a compensatory amount of
inclination which corresponds to a predicted amount of inclination
caused the slide due to the eccentric load found.
2. A slide inclination correcting method in press machinery as set
forth in claim 1, the method further comprising the steps of:
detecting an actual amount of inclination of the slide in the
process of forming a work piece; and using the actual amount of
inclination detected to form a compensatory amount of slide
inclination and thereby to level the slide so that the slide and an
upper surface of a bed or bolster become parallel to each
other.
3. A slide inclination correcting apparatus in press machinery as
set forth in claim 1 or claim 2, the method further comprising the
steps of: detecting an actual amount of inclination of the slide in
the process of forming a work piece; using the actual amount of
inclination detected to form a compensatory amount of slide
inclination which corresponds thereto; and correcting the die based
slide inclination correcting data by feeding back to the die based
slide inclination correcting data the compensatory amount of
inclination formed.
4. A slide inclination correcting apparatus in press machinery
having a slide drive mechanism disposed in a top area of a press
machine for driving a slide via a plurality of points to vertically
move it up and down, thereby forming a work piece, the apparatus
comprising: a die based slide inclination correcting data
acquisition means for acquiring a die based slide inclination
correcting data by finding by measurement or computation for each
of dies or die sets an eccentric load that is to develop in the
slide in the process of forming a work piece; a fluid chamber
provided for each of said points; and a slide inclination
correcting means for adjusting in quantity a fluid in the fluid
chamber on the basis of the die based slide inclination correcting
data acquired by the die based slide inclination correcting data
acquisition means and thereby pre-imparting to the slide a
compensatory amount of inclination that corresponds to a predicted
amount of inclination caused the slide due to the eccentric load
found.
5. A slide inclination correcting apparatus in press machinery as
set forth in claim 4, wherein a said slide inclination correcting
means comprises a cylinder having a fluid chamber lying in
communication with said fluid chamber, and that said compensatory
amount of inclination is pre-imparted to the slide by opening and
closing a valve means disposed between the fluid chamber and the
fluid chamber of the cylinder so as to set the fluid in the fluid
chamber free into the fluid chamber in the cylinder.
6. A slide inclination correcting apparatus in press machinery as
set forth in claim 4 or claim 5, the apparatus further comprising:
a slide inclination detecting means for detecting an actual amount
of inclination of the slide in the process of forming a work piece;
and a means for applying to a said slide inclination correcting
means a feedback control on the basis of a data derived from such
detection by said detecting means.
7. A slide inclination correcting apparatus in press machinery as
set forth in claim 6, the apparatus further comprising a means for
correcting said die based slide inclination correcting data with
the slide inclination data derived from detection by the slide
inclination detecting means.
8. A slide inclination correcting method in press machinery as set
forth in claim 1, wherein said compensatory amount of inclination
is pre-imparted to the slide to compensate for the predicted amount
of its inclination due to the eccentric load by supplying fluid
into, or discharging fluid from, a fluid chamber provided for each
of said points for the slide on the basis of said die based slide
inclination correcting data.
9. A slide inclination correcting method in press machinery as set
forth in claim 8, the method further comprising the steps of:
detecting by a slide inclination detecting means an actual amount
of inclination of the slide in the process of forming a work piece;
and applying to fluid pressure in the fluid chamber a feedback
control on the basis of the actual amount of inclination detected,
such that a lower surface of the slide and an upper surface of a
bed or bolster becomes parallel to each other.
10. A slide inclination correcting method in press machinery as set
forth in claim 9, the method further comprising the steps of:
detecting by a slide inclination detecting means an actual amount
of inclination of the slide in the process of forming a work piece;
and correcting the die based slide inclination correcting data by
feeding back to the die based slide inclination correcting data a
compensatory amount of slide inclination derived from the actual
amount of inclination detected.
11. A slide inclination correcting apparatus in press machinery as
set forth in claim 4, wherein the compensatory amount of
inclination corresponding to the predicted amount of inclination
due to the eccentric load is pre-imparted to the slide by a said
slide inclination correcting means when it acts to supply fluid
into, or discharge fluid from, said each fluid chamber on the basis
of a die based slide inclination correcting data as acquired by
said die based slide inclination correcting data acquisition
means.
12. A slide inclination correcting apparatus in press machinery as
set forth in claim 11, the apparatus comprising: a slide
inclination detecting means for detecting an actual amount of
inclination of the slide in the process of forming a work piece;
and a means for applying to fluid pressure in the fluid chamber a
feedback control on the basis of the actual amount of inclination
detected, such that a lower surface of the slide and an upper
surface of a bed or bolster become parallel to each other.
13. A slide inclination correcting apparatus in press machinery as
set forth in any one of claims 4, 11 and 12, wherein the fluid
chamber provided for each of the points constitutes a fluid chamber
for an overload protector.
14. A slide inclination correcting apparatus in press machinery as
set forth in any one of claims 11 to 13, the apparatus comprising:
a or the slide inclination detecting means for detecting the actual
amount of inclination of the slide in the process of forming a work
piece; and a means for correcting the die based slide inclination
correcting data by feeding back to the die based slide inclination
correcting data a compensatory amount of slide inclination derived
from the actual amount of inclination detected.
15. A slide inclination correcting apparatus in press machinery
having a slide drive mechanism disposed in a top area of a press
body for driving a slide via a plurality of points to vertically
move it up and down, thereby forming a work piece, the apparatus
comprising: a die based slide inclination correcting data
acquisition means for acquiring a die based slide inclination
correcting data by finding by measurement or computation for each
of dies or die sets an eccentric load that is to develop in the
slide in the process of forming a work piece; a slide adjustment
mechanism provided for each of said points; and a slide inclination
correction means for pre-imparting to the slide a compensatory
amount of inclination corresponding to a predicted amount of
inclination caused the slide due to the eccentric load, by driving
said each slide adjustment mechanism on the basis of the die based
slide inclination correcting data acquired by said die based slide
inclination correcting data acquisition means.
16. A slide inclination correcting apparatus in press machinery as
set forth in claim 15, wherein an adjustment motor is provided for
said slide adjustment mechanism provided for each of said each
point.
17. A slide inclination correcting apparatus in press machinery as
set forth in claim 15, comprising sets of said slide adjustment
mechanisms with each set comprising a single or a plurality of
slide adjustment mechanisms provided, respectively, with an
adjustment motor.
18. A slide inclination correcting apparatus in press machinery as
set forth in any one of claims 15 to 17, the apparatus further
comprising a means for bringing the press machine when running to a
halt if a relative difference between compensatory amounts of
inclination of different slide adjustment mechanisms exceeds a
pre-established value.
19. A slide inclination correcting apparatus in press machinery as
set forth in any one of claims 15 to 18, the apparatus further
including: a slide inclination detecting means for detecting an
actual amount of inclination of the slide; and a means for applying
to the slide adjustment mechanism a feed back control on the basis
of the actual amount of inclination detected, such that a lower
surface of the slide and an upper surface of a bed or bolster
become parallel to each other.
20. A slide inclination correcting apparatus in press machinery as
set forth in any one of claims 15 to 19, the apparatus comprising:
a or the slide inclination detecting means for detecting an actual
amount of inclination of the slide; and a means for feeding to the
die based slide inclination correcting data a compensatory amount
of inclination derived from the actual amount of inclination
detected.
Description
TECHNICAL FIELD
[0001] The present invention relates to a slide inclination
correcting method and a slide inclination correcting apparatus in
press machinery for correcting an inclination of a slide caused by
an eccentric load that acts thereon in a press machine while the
press machine is in the process of forming, especially a large work
piece or a plurality of work pieces.
BACKGROUND ART
[0002] Many an existing press machine has a construction in which a
slide is movable vertically up and down by a slide drive mechanism
disposed in an upper area of the machine. The slide is used to
carry on its lower surface a die (upper die) while another die
(lower die) is mounted on a bed or bolster in the machine for
forming a work piece between these dies.
[0003] Also, in a press machine that is relatively large in size
and further in what is commonly called a transfer press, one such
slide may often be used to form a plurality of work pieces
simultaneously. In such cases, it has been experienced that
different forming loads applied on the work pieces create an
eccentric load acting on the slide.
[0004] The slide in a press machine is typically moved vertically
up and down as guided on a slide gib laid on a slide body. An
eccentric load if produced acting on the slide may cause the slide
to be inclined. A deviation in position that will then result
between the upper die attached to the slide and the lower die
mounted on the bolster makes it impossible to perform forming with
precision and also let the dies wear off quickly, thus reducing
their life to a large extent.
[0005] Also, an inclination of the slide produces a localized rise
in bearing pressure between the slide gib and the slide guided
thereon, which disadvantageously causes these bearing surfaces to
wear off soon or even the bearing members to seize up so that the
press machine may become no longer operable.
[0006] In an attempt to obviate such disadvantages, there has been
proposed an apparatus in the art that is designed to correct a
slide inclination in a press machine, e. g., as disclosed in JP U
S62-34998. This bulletin discloses a slide inclination correcting
apparatus in a press machine, having a makeup in which a overload
protector designed to protect the slide from an overload has a
fluid chamber therein fed with pressure fluid if a slide
inclination is detected.
[0007] The correcting apparatus disclosed in that bulletin which in
correcting a slide inclination relies on feeding a pressure fluid
into the overload protector upon detecting the slide inclination is
found to leave itself to be desired, however, presenting several
problems. Thus, a time consumed for a pressure to be raised in the
overload protector until the inclined slide is properly leveled and
a limited accuracy with which it is so raised cause the known
apparatus to be of a relatively slow response and limited follow-up
capability and hence to be poor in productivity and limited in the
abilities to make an accurate correction and thus to form work
pieces with precision.
DISCLOSURE OF THE INVENTION
[0008] With the view to circumventing the problems met in the prior
art, it is an object of the present invention to provide a slide
inclination correcting method and a slide inclination correcting
apparatus in press machinery which method and apparatus make it
possible to achieve forming with due precision without impairing
the machine's productivity. The present invention in one aspect
thereof resides in finding by measurement or computation for each
of dies or die sets an eccentric load that is to develop in the
slide in the process of forming a work piece to prepare a die based
slide inclination correcting data for each of the dies or die sets;
and on the basis of the die based slide inclination correcting data
prepared, pre-imparting to the slide a compensatory amount of
inclination which corresponds to a predicted amount of inclination
caused the slide due to the eccentric load found.
[0009] Thus, in order to achieve the object mentioned above, there
is provided in accordance with the present invention in a first
form of implementation thereof a slide inclination correcting
method in press machinery having a slide drive mechanism disposed
in a top area of a press machine for driving a slide via a
plurality of points to vertically move it up and down, thereby
forming a work piece, characterized in that the method comprises
the steps of finding by measurement or computation for each of dies
or die sets an eccentric load that is to develop in the slide in
the process of forming a work piece to prepare a die based slide
inclination correcting data for each of the dies or die sets; and
on the basis of the die based slide inclination correcting data
prepared, pre-imparting to the slide a compensatory amount of
inclination which corresponds to a predicted amount of inclination
caused the slide due to the eccentric load found.
[0010] According to the method described above, an eccentric load
that does develop in the course of forming a work piece to act on a
slide does not causes the slide to be inclined owing to the fact
that a compensatory amount of inclination formed on the basis of a
die based slide inclination correcting data for each of dies or die
sets is pre-imparted to the slide to counteract the eccentric load.
The effects of the method include the ability to form work pieces
with due precision without impairing their productivity. Also,
causing no deviation in position between an upper and a lower die,
the method ensures preventing them from soon wearing off and does
practically increases the die life.
[0011] The method described may specifically include the steps of
detecting an actual amount of inclination of the slide on the basis
of which a compensatory amount of inclination may be applied to the
slide with the slide leveled thereby so that the slide and the
upper surface of a bed or bolster become parallel to each
other.
[0012] This specific method that seeks to maintain parallelism
between the lower surface of the slide and the upper surface of the
bed or bolster permits forming with due precision while impairing
in no way the productivity. Also, causing no deviation in position
between the upper and lower dies, the method ensures preventing
them from soon wearing off and does practically increases the die
life.
[0013] The method described may specifically include the steps of
detecting an actual amount of inclination of the slide in the
process of forming a work piece, using the actual amount of
inclination detected to form a compensatory amount of slide
inclination which corresponds thereto; and correcting the die based
slide inclination correcting data by feeding back to the die based
slide inclination correcting data the compensatory amount of
inclination formed.
[0014] This specific method that allows the die based slide
inclination correcting data to be enhanced in accuracy each time
forming is repeated permits the compensatory amount of slide
inclination that counteracts the eccentric load to be pre-imparted
in each subsequent forming process to the slide in accordance with
the die based slide inclination correcting data with a
progressively increasing accuracy.
[0015] In order to achieve the object mentioned above, the present
invention also provides in a second form of implementation thereof
a slide inclination correcting apparatus in press machinery having
a slide drive mechanism disposed in a top area of a press machine
for driving a slide via a plurality of points to vertically move it
up and down, thereby forming a work piece, characterized in that
the apparatus comprises: a die based slide inclination correcting
data acquisition means for acquiring a die based slide inclination
correcting data by finding by measurement or computation for each
of dies or die sets an eccentric load that is to develop in the
slide in the process of forming a work piece; a fluid chamber
provided for each of said points; and a slide inclination
correcting means for adjusting in quantity a fluid in the fluid
chamber on the basis of the die based slide inclination correcting
data acquired by the die based slide inclination correcting data
acquisition means and thereby pre-imparting to the slide a
compensatory amount of inclination that corresponds to a predicted
amount of inclination caused the slide due to the eccentric load
found.
[0016] According to the apparatus described above, an eccentric
load that does develop in the course of forming a work piece to act
on a slide does not causes the slide to be inclined owing to the
fact that a compensatory amount of inclination formed on the basis
of a die based slide inclination correcting data for each of dies
or die sets is pre-imparted to the slide to counteract the
eccentric load. The effects of the method include the ability to
form work pieces with due precision without impairing their
productivity. Also, causing no deviation in position between an
upper and a lower die, the method ensures preventing them from soon
wearing off and does practically increases the die life.
[0017] Specifically in the apparatus described, a said slide
inclination correcting means may comprise a cylinder having a fluid
chamber lying in communication with said fluid chamber, and the
said compensatory amount of inclination is pre-imparted to the
slide by opening and closing a valve means disposed between the
first mentioned fluid chamber and the fluid chamber of the cylinder
so as to set the fluid in the first mentioned fluid chamber free or
let it escape into the fluid chamber in the cylinder.
[0018] The construction described above permits making a fine
adjustment easily for the slide inclination and, also much being
quicker in response and much better in follow-up capability than
the prior art of supplying pressure fluid into a fluid chamber,
allows the slide leveling to be accomplished promptly and with
precision.
[0019] The apparatus so constructed as described above may further
include a slide inclination detecting means for detecting an actual
amount of inclination of the slide in the process of forming a work
piece; and a means for applying to a said slide inclination
correcting means a feedback control on the basis of a data derived
from such detection by the said detecting means.
[0020] This specific construction that allows the die based slide
inclination correcting data to be enhanced in accuracy each time
forming is repeated permits the compensatory amount of slide
inclination that counteracts the eccentric load to be pre-imparted
in each subsequent forming operation to the slide in accordance
with the die based slide inclination correcting data with a
progressively increasing accuracy.
[0021] The apparatus so constructed as described above may further
include a means for correcting the said die based slide inclination
correcting data with the slide inclination data derived from
detection by the slide inclination detecting means.
[0022] This specific construction which permits a die based slide
inclination correcting data to be renewed on each occasion with an
actual data for slide inclination allows increasing reliability of
the die based slide inclination correcting data.
[0023] In order to achieve the object mentioned before, the present
invention also provides in a third form of implementation thereof a
method in which in pre-imparting a compensatory amount of
inclination to the slide to compensate for the actual amount of its
inclination due to the eccentric load as called for in the first
form of implementation, adopts the step of supplying fluid into and
discharging fluid from, a fluid chamber provided for each of the
said points for the slide on the basis of the said die based slide
inclination correcting data.
[0024] According to this method described above, an eccentric load
that does develop in the course of forming a work piece to act on a
slide does not causes the slide to be inclined owing to the fact
that a compensatory amount of inclination formed on the basis of a
die based slide inclination correcting data for each of dies or die
sets is pre-imparted to the slide to counteract the eccentric load.
The effects of the method include the ability to form work pieces
with due precision without impairing their productivity. Also,
causing no deviation in position between an upper and a lower die,
the method ensures preventing them from soon wearing off and does
practically increases the die life.
[0025] The method described above may further comprise the steps
of: detecting by a slide inclination detecting means an actual
amount of inclination of the slide in the process of forming a work
piece; and applying to fluid pressure in the fluid chamber a
feedback control on the basis of the actual amount of inclination
detected, such that a lower surface of the slide and an upper
surface of a bed or bolster becomes parallel to each other.
[0026] This specific method that seeks to maintain parallelism
between the slide and the upper surface of the bed or bolster
permits forming with due precision while impairing the
productivity. Also, causing no deviation in position between the
upper and lower dies, the method ensures preventing them from soon
wearing off and does practically increases the die life.
[0027] The method described above may further comprise the steps
of: detecting by a slide inclination detecting means an actual
amount of inclination of the slide in the process of forming a work
piece: and correcting the die based slide inclination correcting
data by feeding back to the die based slide inclination correcting
data a compensatory amount of slide inclination derived from the
actual amount of inclination detected.
[0028] This specific construction which permits the die based slide
inclination correcting data to be enhanced in accuracy each time
forming is repeated allows the compensatory amount of slide
inclination that counteracts the eccentric load to be pre-imparted
in each subsequent forming operation to the slide in accordance
with the die based slide inclination correcting data with a
progressively increasing accuracy.
[0029] In order to achieve the object mentioned before, the present
invention also provides in a fourth form of implementation thereof
an apparatus construction wherein in the construction of the second
form of implementation, the compensatory amount of inclination
corresponding to the actual amount of inclination due to the
eccentric load is pre-imparted to the slide by a said slide
inclination correcting means when it acts to supply fluid into, and
discharge fluid from, said each fluid chamber on the basis of a die
based slide inclination correcting data as acquired by the said die
based slide inclination correcting data acquisition means.
[0030] According to the construction described above, an eccentric
load that does develop in the course of forming a work piece to act
on a slide does not causes the slide to be inclined owing to the
fact that a compensatory amount of inclination formed on the basis
of a die based slide inclination correcting data for each of dies
or die sets is pre-imparted to the slide to counteract the
eccentric load. The effects of the method include the ability to
form work pieces with due precision without impairing their
productivity. Also, causing no deviation in position between an
upper and a lower die, the method ensures preventing them from
quickly wearing off and does practically increases the die
life.
[0031] The apparatus described above may comprise a slide
inclination detecting means for detecting an actual amount of
inclination of the slide in the process of forming a work piece;
and a means for applying to fluid pressure in the fluid chamber a
feedback control on the basis of the actual amount of inclination
detected, such that a lower surface of the slide and an upper
surface of a bed or bolster become parallel to each other.
[0032] This specific construction that seeks to maintain
parallelism between the lower surface of the slide and the upper
surface of the bed or bolster permits forming with due precision
while impairing the productivity. Also, causing no deviation in
position between the upper and lower dies, the method ensures
preventing them from quickly wearing off and does practically
increases the die life.
[0033] In the construction described above, the fluid chamber
provided for each of the points preferably constitutes a fluid
chamber for an overload protector.
[0034] The construction described above which permits utilizing a
fluid chamber in the existing overload-protector for each of the
points in performing the correction of a slide inclination allows
the apparatus of the invention to be manufactured economically,
and, impairing in no way the existing overload protector, ensures
that the slide drive mechanism is protected from a overload.
[0035] The apparatus described above may comprise a or the slide
inclination detecting means for detecting the actual amount of
inclination of the slide in the process of forming a work piece;
and a means for correcting the die based slide inclination
correcting data by feeding back to the die based slide inclination
correcting data a compensatory amount of slide inclination derived
from the actual amount of inclination detected.
[0036] This specific construction which permits the accuracy of the
die based slide inclination correcting data to be enhanced each
time forming is repeated allows the compensatory amount of slide
inclination that counteracts the eccentric load to be pre-imparted
in each subsequent forming operation to the slide in accordance
with the die based slide inclination correcting data with a
progressively increasing accuracy.
[0037] In order to achieve the object mentioned before, the present
invention also provides in a fifth form of implementation thereof a
slide inclination correcting apparatus in press machinery having a
slide drive mechanism disposed in a top area of a press body for
driving a slide via a plurality of points to vertically move it up
and down, thereby forming a work piece, characterized in that the
apparatus comprises: a die based slide inclination correcting data
acquisition means for acquiring a die based slide inclination
correcting data by finding by measurement or computation for each
of dies or die sets an eccentric load that is to develop in the
slide in the process of forming a work piece; a slide adjustment
mechanism provided for each of said points; and a slide inclination
correction means for pre-imparting to the slide a compensatory
amount of inclination corresponding to a predicted amount of
inclination caused the slide due to the eccentric load found, by
driving said each slide adjustment mechanism on the basis of the
die based slide inclination correcting data acquired by the said
die based slide inclination correcting data acquisition means.
[0038] According to the construction described above, an eccentric
load that does develop in the course of forming a work piece to act
on a slide does not causes the slide to be inclined owing to the
fact that a compensatory amount of inclination formed on the basis
of a die based slide inclination correcting data for each of dies
or die sets is pre-imparted to the slide to counteract the
eccentric load. The effects of the method include the ability to
form work pieces with due precision without impairing their
productivity. Also, causing no deviation in position between an
upper and a lower die, the method ensures preventing them from
quickly wearing off and does practically increases the die
life.
[0039] Also, designed to make the compensatory amount adjustable
mechanically through a slide adjustment mechanism, this
construction renders the compensatory amount less affected by heat,
and thus allows the slide to be kept leveled with precision. In
addition, being superior in reproducibility as well to hydraulics,
it serves to yield products formed with an increased precision.
[0040] In the apparatus described above, an adjustment motor may be
provided for the said slide adjustment mechanism provided for each
of said each point.
[0041] This construction which permits the slide to be leveled by
driving the slide adjustment mechanism for each of the points
allows the slide in leveling to be adjusted horizontally in both
longitudinal and transverse directions.
[0042] The apparatus described above may comprises sets of the said
slide adjustment mechanisms with each set comprising a single or a
plurality of slide adjustment mechanisms provided, respectively,
with an adjustment motor.
[0043] This construction that permits simply providing an
adjustment motor serves to reduce the number and the cost of parts
and components. Reducing the number of adjustment motors also
simplifies the entire control system.
[0044] The apparatus described above may further comprise a means
for bringing an operation of a press machine when running to a halt
if a relative difference between compensatory amounts of
inclination of different slide adjustment mechanisms exceeds a
pre-established value.
[0045] This construction allows the operating press machine to come
to a halt when the slide is inclined beyond a pre-established value
of inclination for a reason such as an error of entry and provides
a preventive measure against a problem such as an unusual rise in
bearing pressure between the slide and the slide gib which gives
rise to an abnormal wear of the bearing surfaces and eventually a
seizure there, rendering the slide no longer movable up or
down.
[0046] The apparatus described above may further include a slide
inclination detecting means for detecting an actual amount of
inclination of the slide; and a means for applying to the slide
adjustment mechanism a feed back control on the basis of the actual
amount of inclination detected, such that a lower surface of the
slide and an upper surface of a bed or bolster become parallel to
each other.
[0047] This specific construction that seeks to maintain
parallelism between the lower surface of the slide and the upper
surface of the bed or bolster permits forming with due precision
while impairing the productivity. Also, causing no deviation in
position between the upper and lower dies, the method ensures
preventing them from quickly wearing off and does practically
increases the die life.
[0048] The apparatus described above may include a slide
inclination detecting means for detecting an actual amount of
inclination of the slide; and a means for feeding to the die based
slide inclination correcting data a compensatory amount of
inclination derived from the actual amount of inclination
detected.
[0049] This specific construction which permits the accuracy of the
die based slide inclination correcting data to be enhanced each
time forming is repeated allows the compensatory amount of slide
inclination that counteracts the eccentric load to be pre-imparted
in each subsequent forming operation to the slide in accordance
with the die based slide inclination correcting data with a
progressively increasing accuracy.
[0050] These and other features, objects and advantages of the
invention will be more readily understood or apparent to those
skilled in the art from a reading of the following detailed
description of preferred forms of embodiment of the present
invention as illustrated in the various drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] In the accompanying drawings:
[0052] FIG. 1 is a structural view diagrammatically illustrating a
slide inclination correcting apparatus in press machinery that
represents a first form of embodiment of the present invention;
[0053] FIG. 2 is an explanatory view diagrammatically illustrating
an operation of deriving correction data for use in a slide
inclination correcting apparatus in press machinery according to
the present invention;
[0054] FIG. 3 is a graph showing an amount of inclination of a
slide taken with respect to an eccentric load acting on the
slide;
[0055] FIGS. 4A and 4B are diagrammatic explanatory views showing
an inclination detecting means for use in a slide inclination
correcting apparatus in press machinery according to the present
invention;
[0056] FIGS. 5A and 5B are diagrammatic explanatory views showing
the directions of flow of work pieces obtained by adopting a slide
inclination correcting apparatus in press machinery according to
the present invention;
[0057] FIG. 6 is a structural view diagrammatically illustrating a
slide inclination correcting apparatus in press machinery that
represents a second form of embodiment of the present
invention;
[0058] FIG. 7 is a structural view diagrammatically illustrating a
slide inclination correcting apparatus in press machinery that
represents a third form of embodiment of the present invention;
[0059] FIG. 8 is a cross sectional view diagrammatically
illustrating the apparatus taken along the line VIII-VIII in FIG.
7;
[0060] FIG. 9 is a top plan view diagrammatically illustrating a
modification of a slide adjustment mechanism for use in the slide
inclination correcting apparatus in press machinery according the
third form of embodiment of the present invention; and
[0061] FIG. 10 is a top plan view diagrammatically illustrating
another modification of a slide adjustment mechanism for use in the
slide inclination correcting apparatus in press machinery according
the third form of embodiment of the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
[0062] An explanation in detail follows for each of the various
forms of embodiment of the present invention with reference to the
drawing figures briefly described above.
[0063] Now, mention is made of the first form of embodiment of the
invention.
[0064] FIG. 1 shows in a structural view a slide inclination
correcting apparatus in press machinery that constitutes a first
form of embodiment of the invention in which numeral 1 designates a
press machine and numeral 2 denotes a plurality of uprights mounted
to stand on a machine bed (not shown), and having a crown 3
disposed thereon in which a slide drive mechanism 4 is
accommodated.
[0065] The slide drive mechanism 4 for driving a slide 7 includes a
plurality of, e. g., as shown a pair of, eccentric axles 5 for
rotation in opposite directions by a main motor (not shown) and
connecting rods 6, e. g., as shown in a pair, each of which has one
end side carried by the corresponding eccentric axle 5. Each
connecting rod 6 has the other end side pivotally connected to the
upper end of a plunger 9 of each of overload protectors 12 which
are provided for a plurality of sites of the slide 7, e. g., at two
points 8 as shown.
[0066] Each of the overload protectors 12 includes a cylinder 12b
in which a piston 12c made integral with the plunger 9 is
accommodated as movable vertically up and down. The cylinder 12b
has its lower chamber constituted by a fluid (oil) chamber 12a to
which is connected a fluid (oil) chamber 13a in an overload
protector cylinder 13 via a pilot check valve 112. In addition to
the fluid chamber 13a which is small in diameter, the overload
protector cylinder 13 has an air chamber 13b which is large in
diameter. Air is supplied into the air chamber 13b from an air
source 114 via a regulator 115 which regulates air pressure in the
air chamber 13b.
[0067] As shown also, a slide inclination correcting means
designated at 16 includes a cylinder 18 that is large in diameter
and a cylinder 19 that is small in diameter. The cylinders 18 and
19 have accommodated respectively therein a piston 18a that is
large in diameter and a piston 19a that is small in diameter, the
pistons 18a and 19a being made integral with each other and hence
jointly operable. The large diameter cylinder 18 has an air chamber
18b into which air is supplied from the air source 114 via a
regulator 20 and an electromagnetic valve 21 which regulate and
control air pressure in the air chamber 18b. The small diameter
cylinder 19 has a fluid (oil) chamber 19b which is connected via
pilot check valve 122 to the fluid chamber 13a in the overload
protector cylinder 13.
[0068] Here, the pilot check valves 112 and 122 are designed to be
opened and closed by electromagnetic valves 23 and 24,
respectively. The electromagnetic valves 23 and 24 are designed to
be switched on and off by a control means (not shown) on the basis
of die based slide inclination correcting data pre-stored
therein.
[0069] Further shown in FIG. 1 are gibs 25 that guide the slide 7
as it is vertically up and down, and balancers 26, each made of an
air cylinder, that are included to bias the slide 7 upwards.
[0070] An explanation is next given in respect of a method of
correcting inclination of the slide 7, i. g., leveling the slide
being inclined, by using the slide inclination correcting apparatus
described above.
[0071] A press machine which is relatively large in size and a
transfer press are often required to form a work piece that is
large in size or asymmetrical, or to form a plurality of work
pieces simultaneously. In such a press machine, the forming load
acts on the work piece or work pieces which tends to vary from one
site to another, hence development of an eccentric load which
acting on the slide 7 causes the slide 7 to incline.
[0072] The slide 7 inclined causes an upper die carried by the
slide 7 to deviate in position from a lower die mounted on the
machine bed or bolster, and this becomes the cause of a forming
inaccuracy and the dies soon wearing off
[0073] The present invention in one aspect thereof is based upon
the recognition that such a slide 7 inclination due to an eccentric
load that is to develop during a forming operation can on the other
hand be predicted from dies for use. Thus, it has been determined
that pre-preparing a die based slide inclination correction data
for each of dies or die sets individually and pre-imparting a
correction or compensation to the slide 7 for its predicted
inclination on the basis of the die based slide inclination
correcting data allow compensating for an eventual slide
inclination with high precision. And, proper choice of die based
slide inclination correcting data for a particular die set ensures
always achieving a high precision slide inclination compensation
while impairing in no way the press machine's ability to accept a
variety of die sets.
[0074] Accordingly, the first form of embodiment of the present
invention involves pre-preparing a die based slide inclination
correcting data for each of dies or die sets individually, and
storing in a control means the die based slide inclination
correcting data together with a die or die set identification data,
or alternatively entering such data into the control means when the
die or die set is exchanged.
[0075] The die based slide inclination correcting data can be
prepared as follows:
[0076] Where a plurality of work pieces are formed simultaneously,
a difference comes out in the eccentric load that is to develop to
act on the slide 7 between where they are arranged longitudinally
of the press machine 1 and where they are placed transversely of
it. A difference also comes out in the eccentric load that is to
develop to act on the slide between where the slide drive mechanism
4 and the slide 7 are interconnected via two (2) points and where
they are interconnected via four (4) points. Accordingly, a trial
run is adopted in which work pieces are tentatively (pilot) formed
by a given die set mounted on the press machine. Then, an
inclination caused to the slide 7 is measured by a slide
inclination detecting means 30, such as made of gap sensors, as
shown in FIG. 2.
[0077] FIG. 2 shows an example of measuring the inclination of the
slide 7 produced, e. g., where work pieces are formed by two dies
or die sets placed transversely of the press machine. If two
forming loads P1 and P2 are produced acting on the slide 7 and
P1>P2, , the slide 7 is inclined producing a gap of +a in the
front and a gap of -b in the rear and rising towards the front.
[0078] FIG. 3 is a graph showing the amount of inclination of the
slide 7 with respect to the eccentric load in the transverse (front
and rear) direction. The inclination of the slide 7 in the trial
(forming) run for each of dies or die sets individually is measured
to form a die based slide inclination correcting data which is then
stored.
[0079] While the preceding paragraphs described a method of
deriving a die based slide inclination correcting data by
trial-forming work pieces actually, it is also possible to derive
the eccentric load by computation when or from designing dies and
to prepare a die based slide inclination correcting data for each
of dies or die sets individually from the derived eccentric
load.
[0080] An explanation is next given in respect of a method of
correcting inclination of then slide 7 on then basis of the die
based slide inclination correcting data in the manner described
above.
[0081] The operation of forming work pieces using the press machine
1 is initiated by mounting a die set for use onto the press machine
1. When the die set is so mounted, the identification of the dies
used is entered into the control means.
[0082] This allows the control means to read out from the memory
the pertinent die data and die based slide inclination correcting
data pre-stored therein and thus to establish the relevant forming
conditions and to perform the relevant compensation for the
inclination of the slide 7.
[0083] The compensation for the slide 7 inclination may be
performed when the slide 7 lies standstill at its upper dead point.
As an alternative, it may be done after the slide 7 is moved to
descend and immediately before the upper -dies attached to the
slide 7 come into contact with the work pieces placed on the lower
dies.
[0084] Now, assume that the slide 7 has started descending to form
the work pieces using the two die sets. Then, in response to a
signal from, e. g., a rotary cam switch means (not shown) used to
sense the slide 7 descending and the signal indicating arrival of
the slide 7 at its pre-established position, the control means
furnishes the electromagnetic valve 24 with a correction signal on
the basis of the correction data to compensate for a predicted
inclination of the slide 7.
[0085] Turned on by this signal, the electromagnetic valve 24
causes the pilot check valve 122 to be furnished with a pilot
pressure and the same to be thereby opened. This causes fluid (oil)
in the fluid chamber 12a of the overload protector 12 on the side
in which the lower load P2 acts on the slide 7 to flow into the
fluid chamber 19b of the slide inclination detecting means 16. As a
result, a small inclination is imparted to the slide 7 such that
its lower load side is raised by an amount b.
[0086] Thereafter, as forming starts with the upper dies touching
the work pieces, the slide 7 that is pre-compensated for the
inclination in accordance with the predicted eccentric load will be
held leveled to form the work pieces while maintaining its
parallelism with the upper surface of the bolster. Even with the
slide 7, however, that has been compensated for inclination on the
basis of the particular die based slide inclination correcting data
prepared for the particular die sets used, it may still be possible
for some lack of consistency or evenness such as of the thickness
of work pieces yet to cause the slide 7 an inclination
unexpected.
[0087] Thus, in accordance with another aspect of the invention,
such an unexpected inclination of the slide 7 in the forming
operation is kept detected by the slide inclination detecting means
30 and is fed back to the control means where it is used to renew
the die based slide inclination correcting data. Simultaneously, it
is used to serve to effect a feedback control of the switching
operation for the electromagnetic valves 24 so as to rectify the
slide from inclination.
[0088] Thereafter, when forming the work pieces ends with the slide
7 reaching its lower dead point, the pilot check valves 112 are
opened. This causes fluid in the fluid chamber 19b of the slide
inclination detecting means 16 to flow into the fluid chamber 12a
of the overload protector 12, then permitting the slide 7 to
restore its original horizontal position.
[0089] Thus, even for a forming operation in which in addition to
the predicted eccentric load an unexpected eccentric load develops,
it becomes possible to perform the forming operation on the basis
of the die based slide inclination correcting data prepared for
each die set individually, while keeping the slide 7 in-process
rectified from possible inclination. This is an enhanced protection
for the slide 7 against inclination which makes it possible to
achieve precision forming of work pieces without impairing their
productivity.
[0090] Also, in case an excess load develops during the forming
process, the arrangement shown and described including the overload
protector 12 allows the slide drive mechanism 4 to be protected
against the excess load as heretofore by operating the overload
protector cylinder 13 to let the fluid in the fluid chamber 12a
escape into the overload protector cylinder 13.
[0091] In detecting an inclination of the slide 7, it should be
noted that a variety of alternatives are possible. For example,
slide inclination detecting means 30 and 30 may be provided, as
shown in FIG. 4A, at upper ends of posts 32 and 32 mounted to stand
from the bolster 31. Slide inclination detecting means 30 and 30
may also be provided, as shown in FIG. 4B, in walls of uprights 2
and 2. The slide inclination detecting means 30 and 30 are suitably
made each of a gap sensor.
[0092] It should further be noted that adopting a slide inclination
detecting means in accordance with the present invention allows the
degrees of freedom of flow of work pieces and die design to be
improved to a large extent.
[0093] See, for example, FIGS. 5A to 5D which show a tandem press
line in which a pair of press machines are installed. In addition
to a typical forming process as shown in FIG. 5A in which work
pieces are conveyed from the press machine I.sub.1 upstream to the
press machine I.sub.2 downstream to progressively form the work
pieces, it becomes possible to mount a plurality of dies or die
sets 33 onto each of the press machines I.sub.1 and I.sub.2 while
permitting the work pieces to be conveyed in directions as shown by
the arrows in FIGS. 5B to 5D to form the work pieces so in
succession. Thus, the ability to admit different forming loads in
different process steps ensues which improves the degrees of
freedom of the directions in which work pieces are to flow and die
design to a large extent.
[0094] Mention is next made of a second form of embodiment of the
present invention.
[0095] FIG. 6 shows in a structural view a slide inclination
correcting apparatus in press machinery that represents the second
form of embodiment of the present invention in which numeral 1
designates a press machine and numeral 2 denotes a plurality of
uprights mounted to stand on a machine bed (not shown), and having
a crown 3 disposed thereon in which a slide drive mechanism 4 is
accommodated.
[0096] The slide drive mechanism 4 for driving a slide 7 includes a
plurality of, e. g., as shown a pair of, eccentric axles 5 for
rotation in opposite directions by a main motor (not shown) and
connecting rods 6, e. g., as shown in a pair, each of which has one
end side carried by the corresponding eccentric axle 5. Each
connecting rod 6 has the other end side pivotally connected via a
plunger 9 to the top of the slide at a plurality of sites thereof,
e. g., at two points 8 as shown.
[0097] The plunger 9 is supported to be slidably movable up and
down and has its lower end connected to the upper end of a threaded
shaft 10a in each of slide adjustment mechanisms 10 provided for
each of the points 8.
[0098] The slide adjustment mechanisms 10 are provided to adjust
the height variably for different dies or die sets. They each have
the threaded shaft 10a that passes through a gear casing 10b, and a
nut member 10c fitted on the threaded shaft 10a in mesh
therewith.
[0099] The nut member 10c has on its outer surface a worm wheel 10d
fastened thereto which is in mesh with a worm gear 10e. Each worm
gear 10e has a shaft 10f which is coupled to each of adjustment
motors 11 provided for the slide adjustment mechanisms 10,
respectively. Thus, driving each adjustment motor rotates the nut
member 10 via the worm gear 10e and the worm wheel 10d, and
rotating the nut member 10c in one or the other rotary directions
moves the slide 7 up or down to allow the die height to be adjusted
as required.
[0100] The fluid chambers 12a of the overload protectors 12 are
provided below the points 8, respectively.
[0101] The overload protectors 12 are provided to protect the slide
drive mechanisms 4 and so forth from an excess load when the slide
7 is placed under the excess load by letting fluid in a fluid
chamber 12a escape into an overload protector valve 113. Each of
the overload protectors 12 includes a cylinder 12b which is
disposed below the corresponding point 8 and in which a piston 12c
is accommodated lower the threaded shaft 10a as movable up and down
slidably. The space in each cylinder 12b below the piston 12c
constitutes the fluid chamber 12a, which is connected to the
overload protector valve via a logic valve 14 provided for each of
the points 8.
[0102] On the other hand, the fluid chamber 12a in each of the
overload protectors 12 has a slide inclination correcting means 116
connected thereto which is designed to pre-impart to the slide 7 a
compensatory amount of inclination determined from a predicted
amount of the eccentric load acting on the slide, by supplying
fluid into, and discharging fluid from, each of the fluid chambers
12a.
[0103] Each of the slide inclination correcting means 116 as shown
in FIG. 6 includes a fluid pressure source 15 comprising a high
pressure hydraulic (oil pressure) pump 15b and a low pressure
hydraulic pump 15d connected in parallel and adapted to be driven
by a first and a second motor 15a and 15b, respectively It also
includes an electromagnetic valve 117 that controls supply of fluid
from the fluid pressure source 15 into the fluid chamber 12a via a
check valve 118, and an electromagnetic valve 119 that controls
discharging fluid from the fluid chamber 12a into a fluid
reservoir. It further includes a fluid pressure sensing means 120
that senses fluid pressure in the fluid chamber 12a. A signal
derived from such sensing by the fluid pressure sensing means 120
and indicating a fluid pressure in the fluid chamber 12a is entered
into the control means 122, together with a signal representing an
inclination of the slide 7 and derived from detection by the
inclination detecting means 30 made of, e. g., a gap sensor means.
The electromagnetic valves 117 and 119 are designed to be switched
on and off on the basis of die based slide inclination correcting
data previously stored.
[0104] Also shown in FIG. 6 are gibs 25 that guide the slide 7 as
it is vertically up and down, and balancers 26, each made of an air
cylinder, that are included to bias the slide 7 up wards.
[0105] An explanation is next given in respect of a method of
correcting inclination of the slide 7, i. g., leveling the slide
being inclined, by using the slide inclination correcting apparatus
described above.
[0106] As mentioned hereinbefore, a press machine which is
relatively large in size and a press machine called transfer press
are often required to form a work piece that is large in size or
asymmetrical, or to form a plurality of work pieces simultaneously.
In such a press machine, the forming load acts on the work piece or
pieces which tends to vary from one site to another, hence
development of an eccentric load which acting on the slide 7 causes
the slide 7 to incline.
[0107] The slide 7 inclined causes an upper die carried by the
lower surface of the slide 7 to deviate in position from a lower
die mounted on the machine bed or bolster, and this becomes the
cause of a forming inaccuracy and the dies soon wearing off
[0108] As noted previously, the present invention in one aspect
thereof is based upon the recognition that such a slide 7
inclination due to an eccentric load that is to develop during a
forming operation can on the other hand be predicted from dies for
use. Thus, it has been determined that pre-preparing a die based
slide inclination correcting data for each of dies or die sets
individually and pre-imparting a correction or compensation to the
slide 7 for its predicted inclination on the basis of the die based
slide inclination correcting data allow compensating for an
eventual slide inclination with high precision. And, proper choice
of die based slide inclination correcting data for a particular die
set ensures always achieving a high precision slide inclination
compensation while impairing in no way the press machine's ability
to accept a variety of die sets.
[0109] Accordingly, the second form of embodiment of the present
invention again involves pre-preparing a die based slide
inclination correcting data for each of dies or die sets
individually, and storing in a control means 22 the die based slide
inclination correcting data together with a die or die set
identification data, or alternatively entering such data into the
control means 22 when the die or die set is exchanged.
[0110] While the die based slide inclination correcting data can be
prepared, it should be noted that where a plurality of work pieces
are formed simultaneously, a difference comes out in the eccentric
load that is to develop to act on the slide 7 between where they
are arranged longitudinally of the press machine 1 and where they
are placed transversely of it. A difference also comes out in the
eccentric load that is to develop to act on the slide between where
the slide drive mechanism 4 and the slide 7 are interconnected via
two (2) points and where they are interconnected via four (4)
points. Accordingly, a trial run is adopted in which work pieces
are tentatively (pilot) formed by a given die set mounted on the
press machine. Then, an inclination caused to the slide 7 is
measured as in the first form of embodiment by slide inclination
detecting means 30, each made of, e. g., a gap sensors, placed as
shown in FIG. 2.
[0111] FIG. 2 shows an example of measuring the inclination of the
slide 7 produced, e. g., where work pieces are formed by two dies
or die sets placed transversely of the press machine. If two
forming loads P1 and P2 are produced acting on the slide 7 and
P1>P2, , the slide 7 is inclined producing a gap of +a in the
front and a gap of -b in the rear and rising towards the front.
[0112] The graph in FIG. 3 shows the amount of inclination of the
slide 7 with respect to the eccentric load in the transverse (front
and rear) direction. The inclination of the slide 7 in the trial
(forming) run for each of dies or die sets individually is measured
to form a die based slide inclination correcting data which is then
stored.
[0113] While the preceding paragraphs described a method of
deriving a die based slide inclination correcting data by
trial-forming work pieces actually, it is also possible to derive
the eccentric load by computation when or from designing dies and
to prepare a die based slide inclination correcting data for each
of dies or die sets individually from the derived eccentric
load.
[0114] An explanation is next given in respect of a method of
correcting inclination of then slide 7 on then basis of the die
based slide inclination correcting data in the manner described
above.
[0115] The operation of forming work pieces using the press machine
is initiated by mounting a die set for use onto the press machine.
When the die set is so mounted, the identification of the dies used
is entered into the control means 22.
[0116] This allows the control means 22 to read out from the memory
the pertinent die data and die based slide inclination correcting
data pre-stored therein and thus to establish the relevant forming
conditions and to perform the relevant compensation for the
inclination of the slide 7.
[0117] The compensation for the slide 7 inclination may be
performed when the slide 7 lies standstill at its upper dead point.
As an alternative, it may be done after the slide 7 is moved to
descend and immediately before the upper dies attached to the slide
7 come into contact with the work pieces placed on the lower dies.
A further alternative is to do it for a time period after the slide
7 starts descending from its upper dead point and until the upper
dies attached to the slide comes into contact with the work
pieces.
[0118] Now, assume that the slide 7 has started descending to form
the work pieces using the two die sets. Then, in response to a
signal from, e. g., a rotary cam switch means (not shown) used to
sense the slide 7 descending and the signal indicating arrival of
the slide 7 at its pre-established position, the control means 22
in order to compensate for a predicted inclination of the slide 7
furnishes the electromagnetic valves 117 and 119 with a correction
signal on the basis of the die based slide inclination correcting
data to control supplying fluid into, and-discharging fluid from,
the fluid chambers 12a, thereby pre-imparting to the slide 7 a
compensatory amount of inclination in the manner stated below.
[0119] Thus, the electromagnetic valve 119 in communication with
the fluid chambers 12a in the rear side of the slide where the
lower load P2 acts on the slide 7 during forming is turned on to
discharge fluid in that fluid chamber 12a, thereby raising the rear
side of the slide 7 relatively by an amount b.
[0120] It should be noted that if the slide 7 inclination due to
the eccentric load is minute, the high pressure hydraulic pump 15b
by the motor 15a may be driven and the electromagnetic valve 117
may also be turned on to supply high pressure fluid into the fluid
chamber 12a located in the front side of the slide 7 where the
higher forming load P1 acts on the slide so that the amount of
compression of the pressure fluid in that fluid chamber 12a of the
slide 7 may be reduced and thus to lower the front side of the
slide 7 relatively by an minute amount a.
[0121] It is also possible to relatively raise the rear side of the
slide 7 where the lower forming load P2 acts on the slide by
discharging through the electromagnetic valve 119 fluid in the
fluid chamber 12a located in the rear side of the slide where the
lower forming load P2 acts on the slide and simultaneously to
relatively lower by a minute amount the front side of the slide 7
where the higher forming load P1 acts on the slide by supplying
through the high pressure pump 15b fluid into the fluid chamber 12a
located in the front side of the slide 7 where the higher forming
load P1 acts on the slide.
[0122] As a result, a compensatory amount of inclination that is
commensurate with a predicted eccentric load is pre-imparted to the
slide 7 before forming the work pieces is started.
[0123] Thereafter, as forming starts with the upper dies touching
the work pieces, the slide 7 that is pre-compensated for the
inclination in accordance with the predicted eccentric load will be
held leveled to form the work pieces while its lower surface
maintaining parallelism with the upper surface of the bolster. Even
with the slide 7, however, that has been compensated for
inclination on the basis of the particular die based slide
inclination correcting data prepared for the particular die sets
used, it may still be possible for some lack of consistency or
evenness such as of the thickness of work pieces yet to cause the
slide 7 an inclination unexpected.
[0124] Thus, in accordance with another aspect of the invention,
such an unexpected inclination of the slide 7 in the forming
operation is kept detected by the slide inclination detecting means
30 and is fed back to the control means 22 where it is used to
renew the die based slide inclination correcting data.
Simultaneously, it is used to serve to effect a feedback control of
the switching operations for the electromagnetic valves 117 and 119
and thus of the fluid pressures in the fluid chambers 12a so as to
rectify the slide 7 from inclination.
[0125] Thereafter, when forming the work pieces ends with the slide
7 reaching its lower dead point, the low pressure hydraulic pump
15d by the motor 15c is driven and also the electromagnetic valve
119 is turned off to cause low pressure fluid to be supplied by the
low pressure hydraulic pump 15d into the fluid chamber 12a located
in the rear side of the slide 7, thus permitting the slide 7 to
restore its original horizontal position.
[0126] If high pressure fluid has been supplied by the high
pressure hydraulic pump 15b into the fluid chamber 12a located in
the front side of the slide 7 and the amount of compression of
pressure fluid in the fluid chamber 12a thereby reduced, it should
be noted that the fluid pressure in that fluid chamber 12a in the
front side of the slide 7 will be drained via the electromagnetic
valve 119 into the reservoir, thus permitting the slide 7 to
restore its original horizontal position.
[0127] Also, if fluid in the fluid chamber 12a located in the rear
side of the slide 7 has been drained via the electromagnetic valve
119 into the reservoir and high pressure fluid has been supplied
into the fluid chamber 12a located in the front side of the slide 7
to lower the front side of the slide 7 by a minute amount, it
should be noted that low pressure fluid will be supplied by the low
pressure hydraulic pump 15d into the fluid chamber 12a located in
the rear side of the slide 7 and pressure fluid in the fluid
chamber 12a located in the front side of the slide 7 will be
drained into the reservoir, thus permitting the slide 7 to restore
its original horizontal position.
[0128] Thus, even for a forming operation in which in addition to
the predicted eccentric load an unexpected eccentric load develops,
it becomes possible to perform the forming operation on the basis
of the die based slide inclination correcting data prepared for
each die set individually, while keeping the slide 7 in-process
rectified from possible inclination. This is an enhanced protection
for the slide 7 against inclination which makes it possible to
achieve precision forming of work pieces without impairing their
productivity.
[0129] Also, in case an excess load develops during the forming
process, the arrangement shown and described including the logic
valve 14 allows the slide drive mechanism 4 to be protected against
the excess load as heretofore since the logic valve then operates
to let the fluid in the fluid chamber 12a escape into the overload
protector valve 113.
[0130] In detecting an inclination of the slide 7, it should be
noted that a variety of alternatives are possible in the second
form of embodiment as well. For example, slide inclination
detecting means 30 and 30 may be provided, as shown in FIG. 4A, at
upper ends of posts 32 and 32 mounted to stand from the bolster 31.
Slide inclination detecting means 30 and 30 may also be provided,
as shown in FIG. 4B, in walls of uprights 2 and 2. The slide
inclination detecting means 30 and 30 are suitably made each of a
gap sensor.
[0131] It should further be noted that adopting a slide inclination
detecting means in accordance with the present invention allows the
degrees of freedom of flow of work pieces and die design to be
improved to a large extent.
[0132] See, for example, FIGS. 5A to 5D which show a tandem press
line as in the first form of embodiment in which a pair of press
machines are installed. In addition to a typical forming process as
shown in FIG. 5A in which work pieces are conveyed from the press
machine I.sub.1 upstream to the press machine I.sub.2 downstream to
progressively form the work pieces, it becomes possible to mount a
plurality of dies or die sets 33 onto each of the press machines
I.sub.1 and I.sub.2 while permitting the work pieces to be conveyed
in directions as shown by the arrows in FIGS. 5B to 5D to form the
work pieces so in succession. Thus, the ability to admit different
forming loads in different process steps ensues which improves the
degrees of freedom of the directions in which work pieces are to
flow and die design to a large extent.
[0133] Next, mention is made of a third form of embodiment of the
present invention.
[0134] FIG. 7 shows in a structural view a slide inclination
correcting apparatus in press machinery that constitutes the third
form of embodiment of the present invention in which numeral 1
designates a press machine and numeral 2 denotes a plurality of
uprights mounted to stand on a machine bed (not shown), and having
a crown 3 disposed thereon in which a slide drive mechanism 4 is
accommodated.
[0135] The slide drive mechanism 4 for driving a slide 7 includes a
plurality of, e. g., as shown a pair of, eccentric axles 5 for
rotation in opposite directions by a main motor (not shown) and
connecting rods 6, e. g., as shown in a pair, each of which has one
end side carried by the corresponding axle 5. Each connecting rod 6
has the other end side pivotally connected via a plunger 9 to the
top of the slide at a plurality of sites thereof, e. g., at two
points 8 as shown.
[0136] The plunger 9 is supported by the crown 3 to be slidably
movable up and down and has its lower end connected to the upper
end of a threaded shaft 10a in each of slide adjustment mechanisms
10 provided for each of the points 8, respectively.
[0137] The slide adjustment mechanisms 10 are provided to adjust
the die height variably for different dies or die sets. They each
have the threaded shaft 10a that passes through a gear casing 10b,
and a nut member 10c fitted on the threaded shaft 10a in mesh
therewith.
[0138] The nut member 10c has on its outer surface a worm wheel 10d
fastened thereto which is in mesh with a worm 10e.
[0139] Each worm 10e has a shaft 10f which as shown in FIG. 8
projects horizontally from the gear casing 10b and is coupled to
each of adjustment motors 11 provided for the slide adjustment
mechanisms 10, respectively.
[0140] The adjustment motors 11 are controllably connected to a
control means 222 such that driving with its commands the
adjustment motors simultaneously moves the slide 7 vertically
up/down to allow the die height to be adjusted as required.
[0141] The control means 222 is provided with a slide inclination
correcting means 216 for pre-imparting a compensatory amount of
inclination determined by a predicted eccentric load acting on the
slide 7. Thus, controlling the drive of each of the adjustment
motors 11 individually pre-imparts to the slide 7 a compensatory
amount of inclination determined by a predicted eccentric load.
Each adjustment motor 11 also has a slide position sensing means
214 such as an encoder connected thereto for detecting the position
of the slide 7 at each of the points 8, and a position indicating
signal from the sensing means 214 is input into the control means
222, together with a signal from the slide inclination detecting
means 214, each made of, e. g., a gap sensor, for detecting an
actual inclination of the slide 7.
[0142] In FIG. 7 there are also shown overload protectors 12 each
of which is arranged below each of the points 8, respectively, and
fluid chambers 12a. Each of the fluid chambers 12a is connected to
an overload protector valve (not shown) arranged so that
development of an excess load on the slide during the forming
process sets fluid in these fluid chambers 12a free into the
overload protector valve, thereby preventing the slide drive
mechanism 4 from damaging by the excess load.
[0143] Further shown in FIG. 7 are gibs 25 that guide the slide 7
as it is vertically up and down, and balancers 26, each made of an
air cylinder, that are included to bias the slide 7 upwards.
[0144] An explanation is next given in respect of a method of
correcting inclination of the slide 7, i. g., leveling the slide
being inclined, by using the slide inclination correcting apparatus
described above.
[0145] As mentioned hereinbefore, a press machine which is
relatively large in size and a press machine called transfer press
are often required to form a work piece that is large in size or
asymmetrical, or to form a plurality of work pieces simultaneously.
In such a press machine, the forming load acts on the work piece or
pieces which tends to vary from one site to another, hence
development of an eccentric load which acting on the slide 7 causes
the slide 7 to incline.
[0146] The slide 7 inclined causes an upper die carried by the
lower surface of the slide 7 to deviate in position from a lower
die mounted on the machine bed or bolster, and this becomes the
cause of a forming inaccuracy and the dies soon wearing off
[0147] As noted previously, the present invention in one aspect
thereof is based upon the recognition that such a slide 7
inclination due to an eccentric load that is to develop during a
forming operation can on the other hand be predicted from dies for
use. Thus, it has been determined that pre-preparing a die based
slide inclination correcting data for each of dies or die sets
individually and pre-imparting a correction or compensation to the
slide 7 for its predicted inclination on the basis of the die based
slide inclination correcting data allow compensating for an
eventual slide inclination with high precision. And, proper choice
of die based slide inclination correcting data for a particular die
set ensures always achieving a high precision slide inclination
compensation while impairing in no way the press machine's ability
to accept a variety of die sets.
[0148] Accordingly, the third form of embodiment of the present
invention again involves pre-preparing a die based slide
inclination correcting data for each of dies or die sets
individually, and storing in a control means 222 the die based
slide inclination correcting data together with a die or die set
identification data, or alternatively entering such data into the
control means 222 when the die or die set is exchanged.
[0149] While the die based slide inclination correcting data can be
prepared, it should be noted that where a plurality of work pieces
are formed simultaneously, a difference comes out in the eccentric
load that is to develop to act on the slide 7 between where they
are arranged longitudinally of the press machine 1 and where they
are placed transversely of it. A difference also comes out in the
eccentric load that is to develop to act on the slide between where
the slide drive mechanism 4 and the slide 7 are interconnected via
two (2) points and where they are interconnected via three (3) or
four (4) points. Accordingly, a trial run is adopted in which work
pieces are tentatively (pilot) formed by a given die set mounted on
the press machine. Then, an inclination caused to the slide 7 is
measured as in the first form of embodiment by slide inclination
detecting means 30, e. g., made of gap sensors, disposed on the
bolster 31 spaced apart each other in the front and the rear as
shown in FIG. 2.
[0150] FIG. 2 shows an example of measuring the inclination of the
slide 7 produced, e. g., where work pieces are formed by two dies
or die sets placed transversely of the press machine. If two
forming loads P1 and P2 are produced acting on the slide 7 and
P1>P2, the slide 7 is inclined producing a gap of +a in the
front and a gap of -b in the rear and rising towards the front.
[0151] The graph of FIG. 3 shows the amount of inclination of the
slide 7 with respect to the eccentric load in the transverse (front
and rear) direction. The inclination of the slide 7 in the trial
(forming) run for each of dies or die sets individually is measured
to form a die based slide inclination correcting data which is then
stored.
[0152] While the preceding paragraphs described a method of
deriving a die based slide inclination correcting data by
trial-forming work pieces actually, it is also possible to derive
the eccentric load by computation when or from designing dies and
to prepare a die based slide inclination correcting data for each
of dies or die sets individually from the derived eccentric
load.
[0153] An explanation is next given in respect of a method of
correcting inclination of then slide 7 on then basis of the die
based slide inclination correcting data in the manner described
above.
[0154] The operation of forming work pieces using the press machine
is initiated by mounting a die set for use onto the press machine.
When the die set is so mounted, the identification of the dies used
is entered into the control means 222.
[0155] This allows the control means 222 to read out from the
memory the pertinent die data and die based slide inclination
correcting data pre-stored therein and thus to establish the
relevant forming conditions and to perform the relevant
compensation for the inclination of the slide 7.
[0156] The compensation for the slide 7 inclination may be
performed when the slide 7 lies standstill at its upper dead point.
As an alternative, it may be done after the slide 7 is moved to
descend and immediately before the upper dies attached to the slide
7 come into contact with the work pieces placed on the lower dies.
A further alternative is to do it for a time period after the slide
7 starts descending from its upper dead point and until the upper
dies attached to the slide comes into contact with the work
pieces.
[0157] Now, assume that the slide 7 has started descending to form
the work pieces using the two die sets. Then, in response to a
signal from, e. g., a rotary cam switch means (not shown) used to
sense the slide 7 descending and the signal indicating arrival of
the slide 7 at its pre-established position, the control means 222
in order to compensate for a predicted inclination of the slide 7
furnishes the adjustment motor 11 in the slide adjustment
mechanisms 10 (provided for the points 8, respectively) with a
correction signal on the basis of the die based slide inclination
correcting data to cause the adjustment motors 11 to drive the
slide 7 via the slide adjustment mechanism 10, thereby
pre-imparting thereto a compensatory amount of inclination in the
manner stated below.
[0158] Thus, the adjustment motor 11 in the slide adjustment
mechanism 10 provided for the point 8 in the front side of the
slide 7 where the higher forming load P1 acts on the slide 7 is
driven to relatively lower that higher forming load, front side of
the slide 7 by an amount a upon rotating the nut member 10c via the
worm 10e and the worm wheel 10d. Alternatively, the adjustment
motor 11 in the slide adjustment mechanism 10 provided for the
point 8 in the rear side of the slide 7 where the lower forming
load P2 acts on the slide 7 is driven to relatively raise that
lower forming load, rear side of the slide 7 by an amount b upon
rotating the nut member 10c via the worm 10e and the worm wheel
10d.
[0159] As an alternative, it should be noted that the slide
adjustment mechanism 10 provided for the point 8 in the front side
of the slide 7 where the higher forming load P1 acts on the slide 7
may be operated to lower that higher forming load, front side of
the slide 7 while the slide adjustment mechanism 10 provided for
the point 8 in the rear side of the slide where the lower forming
load P2 acts on the slide 7 is operated to raise that lower forming
load, rear side of the slide 7, thereby pre-imparting thereto a
compensatory amount of inclination.
[0160] As a result, the compensatory amount of inclination that is
commensurate with a predicted eccentric load is pre-imparted to the
slide 7 before forming the work pieces is started. At the same
time, the position of the slide 7 that has been moved up and down
for each of the points 8 is detected for each of the points by the
slide position sensing means 214 connected to each of the
adjustment motors 11, respectively, and is fed back to the control
means 222. This facilitates, and increases the accuracy of, a fine
adjustment by the slide adjustment mechanisms 10
[0161] It should also be noted that the control means 22 has a
pre-established value stored therein which represents an admissible
limit of inclination of the slide. This arrangement is provided to
prevent development of an abnormal rise in bearing pressure between
the slide gib and the slide guided thereby, which develops when the
slide 7 is inclined beyond such as limit and causes an abnormal
wear of the bearing surfaces and a seizure of the bearing members,
eventually rendering the slide 7 incapable of moving up and down.
To this end, the control means 222 compares with the
pre-established as a threshold a position signal from the position
sensing means 214 connected to the adjustment motors 11 for the
slide adjustment mechanisms 10. If the relative difference of their
outputs in magnitude exceeds the pre-established value, an
emergency signal is output from the control means, causing the
running press machine 1 to come to a halt.
[0162] It may be noted that causes that may bring about the amount
of correction by the slide adjustment mechanisms 10 exceeding the
pre-established value include, besides entry by error of a value of
correction, a failure of the position sensing means 214, and a
malfunction of the slide adjustment means 10. If the failure of the
position sensing means 214 is the cause, bringing the press machine
1 to a halt when the pre-established value is exceeded by the
relative difference between signals from the slide inclination
detecting means 30 can doubly ensure its safety.
[0163] Thereafter, as forming starts with the upper dies touching
the work pieces, the slide 7 that is pre-compensated for the
inclination in accordance with the predicted eccentric load will be
held leveled to form the work pieces while its lower surface
maintaining parallelism with the upper surface of the bolster. Even
with the slide 7, however, that has been compensated for
inclination on the basis of the particular die based slide
inclination correcting data prepared for the particular die sets
used, it may still be possible for some lack of consistency or
evenness such as of the thickness of work pieces yet to cause the
slide 7 an inclination unexpected.
[0164] Thus, in accordance with another aspect of the invention,
such an unexpected inclination of the slide 7 in the forming
process is kept detected by the slide inclination detecting means
30 and is fed back to the control means 222 where it is used to
renew the die based slide inclination correcting data.
Simultaneously, it is used to serve to effect a feedback control of
the rotations of the adjustment motors 11 in both rotary directions
and thus of the operations of the slide adjustment mechanisms 10 so
as to rectify the slide 7 from inclination.
[0165] Thereafter, when forming the work pieces ends with the slide
7 reaching its lower dead point, the slide 7 starts rising and the
adjustment motors 11 are so driven that the higher forming load P1,
slide front side if it was lowered by the amount a, or the lower
forming load P2, slide rear side if it was raised by the amount b
by the corresponding slide adjustment mechanism 10 when the
compensatory inclination correction of the slide 7 was effected is
raised by the amount a or lowered by the amount b, respectively,
thereby restoring the slide 7 to its original horizontal
position.
[0166] It should be noted that if the higher forming load P1, front
side of the slide 7 was lowered and the lower forming load P2, rear
side of the slide 7 was raised when the compensatory slide
inclination correction was effected, they are now raised and
lowered, respectively to restore the slide to its original
horizontal position.
[0167] Thus, even for a forming operation in which in addition to
the predicted eccentric load an unexpected eccentric load develops,
it becomes possible to perform the forming operation on the basis
of the die based slide inclination correcting data prepared for
each die set individually, while keeping the slide 7 in-process
rectified from possible inclination. This is an enhanced protection
for the slide 7 against inclination which makes it possible to
achieve precision forming of work pieces without impairing their
productivity.
[0168] Also, in case an excess load develops during the forming
process, the arrangement shown and described allows the slide drive
mechanism 4 to be protected against the excess load as heretofore
by letting the fluid in the fluid chamber 12a escape into the
overload protector valve
[0169] While in the third form of embodiment, a slide adjustment
mechanism 10 is provided for each of the points 8 with one
adjustment motor 11 for each slide adjustment mechanism, it should
be noted that it is possible as in a modification shown in FIG. 9
to provide two sets of slide adjustment mechanisms 10 transversely
of the slide 7 with each set comprising slide adjustment mechanisms
10 arranged longitudinally of the slide 7 and to provide one
adjustment motor 11 for each set so as to drive the slide
adjustment mechanisms in the set simultaneously.
[0170] This modification provides an identical amount of adjustment
longitudinally of the slide 7 but with the ability to impart to the
slide 7 an inclination transversely thereof is particularly
effective to a press forming process in which an eccentric load
develops especially in a transverse direction.
[0171] An alternative modification shown in FIG. 10 provides two
sets of slide adjustment mechanisms 10 longitudinally of the slide
7 with each set having slide adjustment mechanisms 10 arranged
transversely of the slide 7 and one adjustment motor 11 for each
set so as to drive the slide adjustment mechanisms in the set
simultaneously.
[0172] This modification provides an identical amount of adjustment
transversely of the slide 7 but having the ability to impart to the
slide 7 an inclination longitudinally thereof is particularly
effective to a press forming process in which an eccentric load
develops especially in a longitudinal direction.
[0173] In detecting an inclination of the slide 7, it should be
noted that a variety of alternatives are possible in the third form
of embodiment as well. For example, slide inclination detecting
means 30 and 30 may be provided, as shown in FIG. 4A, at upper ends
of posts 32 and 32 mounted to stand from the bolster 31. Slide
inclination detecting means 30 and 30 may also be provided, as
shown in FIG. 4B, in walls of uprights 2 and 2. The slide
inclination detecting means 30 and 30 are suitably made each of a
gap sensor.
[0174] It should further be noted that adopting a slide inclination
detecting means in accordance with the present invention allows the
degrees of freedom of flow of work pieces and die design to be
improved to a large extent.
[0175] See, for example, FIGS. 5A to-5D which show a tandem press
line as in the first form of embodiment in which a pair of press
machines are installed. In addition to a typical forming process as
shown in FIG. 5A in which work pieces are conveyed from the press
machine I.sub.1 upstream to the press machine I.sub.2 downstream to
progressively form the work pieces, it becomes possible to mount a
plurality of dies or die sets 33 onto each of the press machines
I.sub.1 and I.sub.2 while permitting the work pieces to be conveyed
in directions as shown by the arrows in FIGS. 5B to 5D to form the
work pieces so in succession. Thus, the ability to admit different
forming loads in different process steps ensues which improves the
degrees of freedom of the directions in which work pieces are to
flow and die design to a large extent.
[0176] While the present invention has hereinbefore been set forth
with respect to certain illustrative forms of embodiments thereof,
it will readily be appreciated to be obvious to a person skilled in
the art that many alternations thereof, omissions therefrom and
additions thereto can be made without departing from the essences
of scope of the present invention. Accordingly, it should be
understood that the invention is not intended to be limited to the
specific forms of embodiment thereof set forth below, but to
include all possible forms of embodiment thereof that can be made
within the scope with respect to the features specifically set
forth in the appended claims and encompasses all the equivalents
thereof.
* * * * *